Project summary: About five million patients currently suffer from heart failure (HF) in the US, resulting in about one million hospitalizations annually and a yearly cost of > 30 billion USD. The long-term objective of this project is to develop an innovative technology to assist HF outpatient management. The proposed device will be used by health care providers to detect HF deterioration, which may facilitate early therapeutic intervention, and possibly reduced hospitalization, morbidity, cost and potentially mortality. The project is an important step in later building a follow up device for in home monitoring. The technology relies on detecting changes in low-frequency chest wall vibrations due to heart contraction. These sub-audible vibrations can be detected and analyzed with appropriate sensors and digital signal processing methods. The proposed first-generation novel device is not intended for initial diagnosis of HF patients (i.e., distinguishing normal from abnormal subjects); rather it is intended for early ambulatory detection of changes in chest wall vibrations that may be associated with clinical changes in HF individuals. The proposed device would be non-invasive, safe, and require brief measurement time (1-2 minutes) once a week or as needed. All objectives of Phase I were met or exceeded. During Phase II, certain device enhancements will be implemented and a first-generation prototype will be built. The device will be tested in HF subjects during hospitalization and post-discharge. These human studies will help delineate chest vibration correlates of HF status changes. If the project is successful, the proposed novel technology would be used by healthcare providers (and later by HF outpatients at home) as a rapid assessment and monitoring tool during healthcare provider visits. It is expected that the envisioned device would be compact, easy and comfortable to use, rapid, inexpensive and safe.